Multichromatic spraying apparatus



Patented June 27, 1950 MULTICHROMATIC SPRAYING AiPARATUS Edward M. Clarkand Fernand E. Ledecq, Montreal, Quebec, Canada, assignors, by mesneassignments, to The Sherwin-Williams Company, Cleveland, hio,'acorporation of Ohio Application December 11, 1946, Serial No. 715,362

- In Canada September 5, 1946 2 Claims.

This invention relates to improvements in hand-held spraying appliancesof the spray-gun ype The conventional spray gun has a single liquidinlet through which liquid is delivered under pressure to a liquidpassage leading to a liquid discharge nozzle. The discharge orifice ofsaid nozzle is normally closed by a spring-biased needle valve which isopened by a trigger element which also serves to open a normally closedspring-biased air valve controlling the delivery of compressed air to anair nozzle fitted over the'liquid nozzle. The air nozzle is providedwith a central orifice through which atomizing air is delivered in anannular stream enveloping the stream of liquid issuing from the liquidnozzle. The air nozzle is also provided with so-called fanning portsthrough which part of the compressed air is directed against theatomized stream of liquid to effect a flattening or fanning out of saidstream.

Conventional spray guns having a single liquid inlet have long been usedin the paint industry for applying chromatic finishes to variousproduots. With such guns, the application of multichromatic finishes,such as hammered or spot pattern finishes, toned hammer finishes, anddiffused pattern finishes, require several operations since each colouris applied in a separate spray by a separate "gunning procedure.

It has recently been demonstrated'that multichromatic finishes, superiorto those obtained when the component colours are applied by separategunning operations with conventional spray guns, can be obtained by .theuse of a specially designed spray gun through which the componentcolours are simultaneously applied in a single spray. This special gunis provided with separate liquid inlets opening at difierent points intoa single liquid passage in which the component colours are appropriatelymixed or blended immediately prior to being discharged in a single spraythrough the discharge orifice of a liquid nozzle located at thedischarge end of said passage. Each liquid inlet is connected by aseparate conduit to a pressure supply vessel containing one componentcolour of the finish. Removable bushing-type inserts of predeterminedbore dimensions are fitted in the liquid inlets of the gun to controlthe amount of each of the component colours introduced into the liquidpassage of the gun. These inserts are interchangeable with other insertsof different bore dimensions to give difierent flow and pattern effects.

According to this invention the superior multi-component finishesapplied in a single spray by the aforesaid special spray gun'are du-"plicated by the use of a conventional spray gun equipped with amulti-branch adapter attachment having one branch coupled to the singleliquid inlet nipple of the gun and having eachof a plurality ofremaining branches connected, by a separate liquid supply line, to apressure vessel containing one of the component coating materials of themulti-component finish. In this case, the inserts which control the flowand pattern effects are fitted in those branches of the adapterattachment which are connected to the paint or enamel-containingpressure vessels.

A preferred embodiment of the invention is shown in theaccompanying-drawings, in which- Figure l is a side view of aconventional spray gun equipp d with our improved multi-branch adapterattachment and shows the manner \in which the attachment is applied byconnecting one branch thereof to the singl liquid inlet nipple of the.gun and connecting each of the remaining branches to the liquid outletfitting of a liquid pressur vessel containing one of the componentcoating materials of the multi-component finish which is applied, in asingle spray, through the liquid nozzle of the gun.

Figure 2 is a side view of the adapter attachment per se.

In these drawings we have shown a conventional spray gun 5 having aliquid nozzle 6 located at the discharge end of a liquid passage 1. Thedischarge orifice of nozzle 6 is normally closed by a spring-biasedneedle valve 8 which is operated to open position by a conventionalvalve-controlling trigger 9. Liquid is delivered under pressure to asingle liquid inlet nipple l0 opening into liquid passage 1. In the openposition of valve 8 a stream of liquid is discharged from nozzle 6 andis enveloped by an annular stream of atomizing air. discharged throughthe central orifice ll of a conventional air nozzle l2.

3 The. air nozzle is fitted on the liquid nozzle in the usual manner andis provided with conventional fan ports l3 through which compressed airA is directed against the atomized stream of liquid to effect aflattening and fanning out of said stream. A normally closedspring-biased air valve l4 controls air passages in the gun (not shown)through which compressed air is supplied to the central orifice II andfan ports l3 of air nozzle l2. Valve 14 includes a valve stem l5 againstwhich trigger 9 acts to open said valve.

The adapter attachment provided in accordance with our invention isgenerally indicated at l6. It comprises a multi-branch fitting throughwhich the component coating materials of a multi-component finish aredelivered to inlet nipple 10 of gun 5 from suitable pressure vessels l1and I8, each containing one of said coating materials. One branch 19,constituting the outlet branch of fitting I6, is provided at its outerend with a conical portion 20 which is held tightly against a conicalseat Illa of nipple In by a coupling nut 2| which is screwed onto saidnipple and is provided with a clamping flange 22 bearing against ashoulder 23 formed by the conical portion 20. The two remaining branches24 and 25 of'fitting l6 are respectively connected by condu'its 26 and21 to liquid outlet fittings 28 and 29 of pressure vessels I1 and I8.

Bushing-type inserts 30 and 3|, provided with bores 32 and 33 ofpredetermined dimensions, are arranged in the liquid inlet branches 24and 25 of fitting l6. These inserts control the relative amounts of thecomponent coating materials supplied to the liquid inlet 10 of the gunthrough the fitting l6 and are interchangeable with other inserts ofdifierent bore dimensions to give different flow and pattern efiects.

Fitting I6 is internally partitioned, as indicated at 34, to preventpremature mixing of the component coating materials of the finish withinsaid fitting. In this connection, it will be noted that partition 34divides the interior of the fitting into separate flow passages 35 and36 in which the component colours of the finish are kept separate fromeach other until they pass into liquid inlet nipple l0 of spray gun 5.

In the use of the spraying apparatus described multi-component finishare delivered under pressure from vessels l1 and 18 to inlet branches 24and 25 of fitting I6 and pass through the separate flow passages 35 and.36 to the liquid inlet nipple 10. When trigger 9 is operated to openneedle valve 8 and air valve M, the component coating materials aresimultaneously discharged through the discharge orifice of liquid nozzle6 in a single stream which is enveloped by an annular stream ofatomizing air delivered through the central orifice of air nozzle l2 andthe stream of atomized liquid is fiattened'and fanned'out by theimpinging jets of compressed air delivered through the fan ports l3 ofthe air nozzle. The

multi-component pattern effects obtained are We claim:

1. Spraying apparatus for simultaneously applying the component coatingmaterials of a multi-component finish in a single spray comprising aspray gun provided with a spray nozzle and a single liquid inlet openingthrough which all of said coating materials are passed to said nozzle, aplurality of supply vessels each adapted to contain a component coatingmaterial of the multi-component finish, and a multi-branch fittingthrough which the coating materials are delivered to said inlet openingfrom said vessels, said fitting having a. liquid outlet branch connectedto said inlet opening and having a plurality of liquid inlet branchesrespectively connected to said vessels, said outlet branch of thefitting being internally partitioned axially thereof by a generallydiametrically disposed wall to provide separate outlet ductscommunicating respectively at one end with the plurality of inletbranches of the fitting and at their opposite ends with said singleinlet opening, whereby mixing of said component coating materials isprevented while they are simultaneously flowing through the fitting.

2. In spray gun apparatus for simultaneously applying the componentliquidcoating materials of a multi-component finish in a single spray,

said apparatus including a spray gun having a single discharge orificeand a single inlet opening for supplying a plurality of coatingmaterials thereto, a pair of supply vessels for respectively containingtwo diiierent coating materials under pressure, and a pair of conduitsrespectively connected to said vessels for conveying the two coatingmaterials separately to said spray gun; the combination of amulti-branch fitting comprising a pair of inlet branches respectivelyconnected to said conduits for receiving the coating materials therefromand a single outlet branch connected to the single inlet opening of thespray gun for simultaneously feeding the two coating materials thereto,said outlet branch of the fitting being internally partitioned axiallythereof by a generally diametrically disposed wall into twosubstantially parallel ducts for separately conducting the two coatingmaterials from said inlet branches into the spray gun through saidsingle inlet opening as unmixed substantially parallel flowing streams.EDWARD M. CLARK. FERNAND E. LEDECQ.

REFERENCES CITED The following references-are of record in the file ofthis patent:

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